Biosynthetic pathways are engineered to produce high yields of desired products. Engineered biosynthetic pathways employ multiple enzymes, often heterologous to the expression host. The enzymes often produce metabolites foreign to the host, thus resulting in side effects such as flux imbalances, toxicity from metabolite intermediates, and/or a burden from protein overexpression. Protein expression levels may be modulated via plasmid copy numbers and promoter strengths. However, combinatorial titration of individual enzyme expression levels is experimentally tedious, especially for multi-enzyme pathways.
There is a need in the art for efficient methods of producing products of biosynthetic pathways.